Triple-Lok 37° flare tube fittings have been used in the industry since Mr. Parker pioneered the product in the 1930s. The 37° flare fitting is the most popular industrial tube/hose fitting connection in the world.

The Triple-Lok design is quite simple. The tube fitting consists of three pieces: the body, the nut and the sleeve. The tube end is flared at a mating 37° angle and sandwiched between the fitting nose (seat) and the sleeve creating an effective seal between the fitting nose and tube flare or hose.